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TRANSCRIPT
AE-104
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Problems in Pressure Vessel Design
and Manufacture
0. Hellström Ragnar Nilson
AKTIEBOLAGET ATOMENERGISTOCKHOLM SWEDEN 1963
AE-104
PROBLEMS IN PRESSURE VESSEL'DESIGN AND MANUFACTURE,
Oa Hellström Ragnar Nilson
UDDEHOLMS AB, DEGERFORS JÄRNVERK AB ATOMENERGIDegerfors Stockholm
Abstract
The general desire by the power reactor process makers to in-crease power rating and their efforts to involve more advanced thermalbehaviour and fuel handling facilities within the reactor vessels areaccompanied by an increase in both pressure vessel dimensions andvarious difficulties in giving practical solutions of design materialsand fabrication problemsa In any section of this report it is emphasizedthat difficulties and problems already met with will meet again in thefuture vessels but then in modified forms and in many cases more per-tinent than before» As for the increase in geometrical size it can bepostulated that with use of better materials and adjusted fabricationmethods the size problems can be taken proper care of« It seems likelythat vessels of sufficient large diameter and height for the largest poweroutput, which is judged as interesting in the next ten year period, canbe built without developing totally new site fabrication technique» It is,however, supposed that such a fabrication technique will be feasiblethough at higher specific costs for the same quality requirements asobtained in shop fabrication»
By the postulated use of more efficient vessel material withprincipally the same good features of easy fabrication in'»differentstages such as preparation, welding, heat treatment etc as ordinaryor slightly modified carbon steels the increase in wall thickness mightbe kept low. There exists, however, a development work to be donefor low-alloy steels to prove their justified use in large reactor pressurevessels,1
Paper presented to the EAES Symposium "KEY PROBLEMS OF NUCLEARPOWER STATIONS LIKELY TO BE BUILT DURING THE NEXT TEN YEARS"at Cannes, France, 8 -12 October 1962.
Printed and distributed in May 1963'.
CONTENTS
Page
Introduction 3
Survey of Swedish Reactor Vessels 6
1. Åge sta PHWR Vessel 6
2. Marviken BHWR Vessel 9
3. Project study PHWR-400 Vessel 11
4. Project study Bashful-500 Vessel 12
Vessel steels and strength evaluation 14
Fabrication in shop or at site 1 8
Special shop requirements due to siEe, weight and design
of the vessel 19
Shop fabrication and inspection 20
Summary 24
Figures 1-27 I - XVIH
REFERENCE REMARK
This paper is of course only one contribution among many to a morecomplete picture of the Swedish development work for nuclear powerstations. At the Cannes symposium other important developmentproblems are stated in the following paper: "Major Problems andDevelopment Tests for Heavy Water Pressure Vessel Reactors"by P H Margen.
- 3 -
Introduction
The nuclear power reactor development work in Sweden has since
1958 been lined up with practically total concentration upon heavy water
reactors of the pressure vessel design type. The first demonstration
of this reactor type in Sweden, the Åge sta PHWR reactor is now in the
later stages of construction and will finally be put in order for critica-
lity and the following research program of first core physics and thermal
behaviour and further stepwise increasing power production tests in the
beginning of 1963, This reactor has been described at different occasions
during the last years at conferences and in technical magazines and in
this report design features by its vessel are given mainly
in order to create a reference point in the discussion of design and ma-
nufacture problems by large reactor pressure vessels. Problems of
various kinds which has been treated and brought to practical solutions,
in the different stages of the work upon the Ågesta vessel are doubtless
forming a fertile ground in the work with the following pressure vessels
which since some time are brought to more or less detailed pre-project
studies for our future power reactor program. From the general point
of view the Ågesta reactor - in itself too small and in many features
suspected to be too complicated and technologically too "luxurious" to
be claimed an economical power production unit - might be regarded
as starting point for two attractive outlines of pressure vessel unit
developments for competitive nuclear power, namely
a) the uniform lattice reactor ("homogenized"), PHWR, and
b) the natural circulation direct cycle boiling reactor equipped with
facilities for nuclear superheating, BHWR,
Both these reactors are studied for electricity outputs up to the
order of 400 to 500 MWe and the consequenses in design and manufac-
turing of the adequate pressure vessels are considered. It can be seen
from the following report, that even if the Ågesta vessel must be re-
garded as large and heavy the vessels required for the future reactors
are still larger. With respect to most factors which influence the
_ 4 -
judgment of their feasibility really important extrapolations of the
engineering achievements of today have to be established»
In the question of which reactor pressure vessel is likely to be
built next in Sweden it might be pointed out that a redesign work of
the Marviken Power Plant according to an BHWR lay-out is now going
on for an output size of 200 MWe - when internal nuclear superheating
is included - and that a formal decision on construction can be expected
during the first months of 1963. Planned date for power operations
o£ this unit is 1968. Full scale units - about 500 MWe output - of BHWR
or PHWR might in Sweden be requested for commercial operation in
the beginning of the \c)10'fst
Before going over to the more detailed descriptions of the different
problems it might be proper to lay down some background aspects for
heavy vessels for nuclear reactor purpose. Design, manufacturing,
inspection and use of pressure vessels for different purposes are in
most countries subjected to more or less rigorous regulations and the
application within a new field is consequently among other always re-
garded from the "Pressure Vessel Code" point of view. In 1956 the
regulation aspects in USA were brought to a more common formal basis
by the establishing of the ASME Boiler and Pressure Vessel Code In-
terpretation Case No 1224 (Special Ruling), which then time to another
was completed by definitions and addenda.
In the beginning of 1958 the tentative regulations were brought
together in Case No 1234, which gives the Code aspects upon all pressure
vessels working in the primary reactor circuit or aside from that in such
circuits which still carry reactor coolant containing lethal substances.
Quotation from the interpretation Case No 1234 is made here:
"inquiry: Under what special rules shall a nuclear reactor vessel
or a primary vessel, as defined in Case No 1224, be built in order to
be built in order to be acceptable for Code construction?
- 5 -
Reply: Pending development of more complete rules to cover
nuclear vessels, it is the opinion of the Committee that a reactor
vessel or a primary vessel shall meet the requirements of this Case
in order to meet the intent of the Code and to be stamped in accordance
•with Case No 1224. Where differences exist the requirements of this
Case take precedence over the Code rules for the subjects covered.
The requirements of this Case are as follows? (t), (2) -----(6), (7)
and (8)."
The design calculation, general specification of materials, wel-
ding fabrication and inspection rules given in the items (1) to (6) are
quite well defined additions to and restrictions of normal Code regu-
lations and do not cause much trouble in their interpretation and
technical application.
The items (7) and (8) are of quite another character and do in
fact contain general descriptions of what to be taken special care of
when designing advanced vessels, specially nuclear vessels. Quota-
tion follows here;
"(7) The Code rules are intended to provide minimum safety
requirements for new construction, and not to cover deterioration
which may occur in service as a result of corrosion, erosion, ra-
diation effects, instability of the materials or operating conditions
such as transient thermal stress or mechanical shock and vibratory
loading; nevertheless particular consideration shall be given to these
effects with a view of obtaining the desired life of the vessel.
(8) In view of these severe service requirements, particular
consideration shall also be given to materials, construction, and
inspection, including supplementary methods of non-destructive
testing, so that soundness and good practice will result. Due regard
shall be given to such items as smoothness of welds and to location
and detail of structural attachments. "
- 6 -
Since 1958 there has of course been added more detailed pro-
visional rules and recommendations both by the ASME Boiler and
Pressure Vessel Committee and by safeguard authorities and
societies in other countries,for instance by Lloyd's Register of
Shipping, Land Division, in the Provisional Requirements, 1960.
These rules - later on collected for instance within the ASME
Nuclear Code Cases No 1270 N, 1271 N, 1272 N, 1273 N, 1274 N
and their addenda - do still mostly refer to problems of the same
defined character as covered by the items (1) to (6) above and the
items (7) and (8) still are in principle as generally given as in 1958.
It is easy to see that the problems which are not distinctly covered
by Code rules may cause the engineer more trouble than those which
are covered. It is further quite obvious that the questions which are
not covered by Code rules may have a great and perhaps dominant
effect upon fabrication and construction costs.
As the evaluation of all these questions on the basis of experienced
correlations between used design and intended vessel usage and real
vessel behaviour during operation still is poor or lacking, it must be
stated that sufficient background for a verified economically optimized
design work does not yet exist.
Survey of Swedish Reactor Vessels
A schematic study in size growth for these vessels is demonstra-
ted in Fig. 15 on figure page XIII after the text.
The Åge sta reactor vessel is shown in Fig, 1, 2, 3 and 4 - figure
pages I - IV after the text - and the principle data are to be found in
table 1 at the end of this survey chapter on page f 3. Specially interes-
ting parts of the vessel are:
- 7 -
Bottom dome is of ellipsoid! c al shape with the main nozzles for
inlet and outlet of the coolant. Originally this dome was assumed to be
made with a spherical crown radius for the central portion and with a
torus radius for the outer knuckle portion. From extensive strain
measuring on a scale model, however, it was gathered that the com-
bination of large nozzles and their full reinforcement would give
stresses of somewhat irritating magnitude for a nuclear vessel. As a
result the shape was changed to ellipsoidical which was judged to give
diminished stresses particularly around the nozzles. The theoretical
examination was confirmed by the strain measurement results obtained
for the full scale vessel in connection with the final pressure test.
The flat top cover is equipped with light water circulation for
balanced heating and cooling guided by and controlled against the reac-
tor coolant temperature. The height of top cover is dictated not only
by the need to keep weld seam stresses low but also by the requirement
that radiation dose should be kept at low rates for the upper closing
plate and the tightening flange so that the top plate could be accessible
whenever the reactor is shut down.
The top cover is penetrated by standpipes for fuelling operation
and application of control rod drives. As this reactor has intermittent
fuelling operation at rather short intervals the standpipe closures will
be handled quite many times (roughly 200) during the desired total opera-
tional lifetime. If,these closures are maintainable at non-leakage con-
ditions will be an interesting experience.
The special flange design - the type is shown in Fig. 8 - which
permits reactor starting-up and shut-down operations performed within
10 hours each without producing any overstresses in neither the
vessel nor the top cover, The flange in itself is tightened by a primary
lensformed silver gasket and a secondary seal-welded torus.
All the internal vessel equipment - shielding komponents and
water distribution box etc. - is adapted for remote handling by special
- 8 -
decomposition and lifting gages and the vessel itself can be remote
control lifted out of the concrete biological shielding.
A delicate problem was formed by the demand for very narrow
tolerances for vessel roundness and axial alignment.
All heavy water wet surfaces are claimed to be stainless steel
clad and surface finish in order to prevent contamination was demanded
to be high quality, microdepth of profile in the order of 0. 016 mm. The
stainless cladding was permitted to be supplied as roll-clad or as
deposit weld clad,
A special feature which might be regarded as quite conservative
is the arrangement of neutron and thermal shielding. The radial shiel-
ding is made from stainless steel cylindrical shells concentrically
placed with a very thin annular ring space between and are together
forming 1 50 mm steel between the outer radius of the core reflector
and the vessel wall. Thus the integrated irradiation dose on the wall
will be quite modest even for a core of higher thermal power than the
actual one. Furthermore special channels for boxes containing test
pieces of vessel steel are arranged in the outer portion of the radial
stainless steel shielding. This boxes are remotely handled by a special
machine for removal and transport to test facilities, where control
results of irradiation embrittlement of the vessel steel can be obtained
from time to time.
In order to verify intended design decisions different component
investigations were carried out. One of these investigations is represen-
ted here by Fig. 10, showing scale model of the vessel. That model
was investigated for stress concentrations in the different parts of
tank and lid and subjected to pressure cycling in order to verify the
leak tightness of the primary silver gasket arrangement. Bottom dome
shape modification was initiated by the test results. Another study is
shown in Fig. 11, which illustrates a detailed study of a flat lid portion
- 9 -
including the part of the standpipe which penetrates the lid. Investiga-
tion of stresses and deformations behaviour under thermal cycling and
examination of welding procedure were the preset aims of this work,
which gave some valuable hints to detail modifications.
2. _ Marviken BHWRJVessel
The Marviken reactor is just now - as mentioned in the intro-
duction of this report - in a redesign period. The reactor vessel is
shown in Fig. 5, 6, 7 and 8 - figure pages V - VIII after the text -
and the principal data are listed in table 1 on page T 3, All features
given in this report belong to the redesign version although some
of them, e.g. the internal fuel element manipulator, which gives
the vessel height, can be found in an earlier PHWR version for Mar-
viken.
While the Ågesta vessel has a lot of standpipes for refuelling
the Marviken vessel is equipped with only one loading channel pene-
tration. As the control rod hydraulic drives are arranged internally
at the top of core shroud, penetrations for these drive units are
eliminated from the vessel itself. The cylindrical vessel shell is
penetrated by feed water piping for control rod drives, medium sized
steam piping for pressure relief valves, small size piping for emer-
gency cooling of boiler fuel elements and fuel canning leak detection
and medium sized piping for emergency cooling of superheater fuel
elements. Those penetrations can be assembled within a rather loca-
lized cylinder shell ring portion which has to be reinforced by increase
of wall thickness. Outside of that region the cylinder shell is quite
clean and straight.
The severe penetrations problems are concentrated to the bottom
dome where 30 superheater nozzles and some other single position
penetrations are arranged. The bottom dome design and manufacture
will undöubtly form a work of highest,qualification and careful studies
of what should be the detailed technical decisions are underway. Among
- 10 -
those studies special attention is paid to the superheater nozzle itself,
illustrated in Fig. 7, Calculation - eventually followed by model tests -
upon thermal charge and temperature distribution of the nozzle are
carried out intensely and the consequences for the steam flow correctly
balanced isolation from the nozzle body are estimated. The design
involves also some rather intricate problems of compatibility between
different structural materials.
The main design problems with this large vessel can - aside
from the special bottom dome problems - be listed as follows
a) demonstration of the use of low-alloy vessel steel in order to reduce
vessel weight and to give medium wall thickness for high quality
welding and inspection,
b) realistic efforts to get away from specifications of costly narrow
tolerances in shape and measures,
c) liberalizing of the restrictions upon cladding materials and surface
finish quality,
d) the application of a suiting flange design in view of the fact that
the main tightening will be opened only for major rearrangements
of the internal reactor equipment, which cannot be carried out by
the system of internal manipulator and outer facilities for fuel
element and control rod handling. In this question it might be noticed,
first, that the Åge sta flange type according to Fig, 8 is not as fully
justified by this vessel behaviour as by Åge sta with its flat lid design,
second that the Agesta type seems to be somewhat unfavourable in
dimensions and weight, especially for the bolts, at this vessel size
and higher pressure, and third that the care against thermal transient
loads and moments in the flange region of the vessel would cause a
need for development work upon principally new flange types. Such
types are studied since some time and good prospects of a flange
design, in which the influence of excentric loading and thermal
forces is eliminated, seem to exist.
- 11 -
In this reactor vessel the neutron and thermal shielding is acquired
by a somewhat different arrangement than by the Ågesta vessel. Theore-
tical and experimental research has given verifying contribution to this
arrangement, which will use a comparatively thin radial stainless steel
shield combined with a thicker layer of heavy water between the steel
shield and the vessel wall. The efficiency of this method seams to be
superior to that of using thick stainless steel shielding with exception
for the fact that an increase in heavy water inventory could result.
The width of the annular ring space for heavy water outside of the steel
shielding is, however, in this case also needed for the thermal process
water flow. It can be foreseen that the arrangement of test specimen
channels for time to time watching of the irradiation damage on vessel
wall steel would still be kept as an operation condition for this vessel
as it is for the Ågesta vessel.
;PHWR:400Ve s sel
A principal drawing of this pressure vessel is shown in Fig, 9 -
figure page IX after the text - and the principle data are listed in table 1
on page 13 . Special features for this vessel are
a) top dome lid is to be removed at each fuel handling occasion as the reactor
is projected to have a fuel handling procedure similar to that of light
water reactors,
b) hemispherical bottom dome design requires some considerations with
respect to the main inlet and outlet nozzles which are positioned up
in the cylinder flange region of the dome. The control rod drive pene-
trations in the central zone of the hemisphere would not give major
trouble.
As these technical applications have been verified in rather many
cases before this study it seems correct to postulate that most of the
considerations will be i*eiterated verification of the soundness and good
sense in design modifications initiated by different manufacturing methods.
- 12 -
In addition some development work might be included upon more exact
calculation methods for reinforcements in transition regions disturbed
by bending moments.
Ye ssel
The reactor vessel of this study appears in this report mostly in
table 1 on page 13, where the principal data are given for comparison
with Marviken BHWR,
Table 2 on page T7 shows some speculations around needed vessel
wall thicknesses by the use of different vessel steels.
- 13 -
Table 1. Survey of Reactor Data
Core diameter mCore height m
Radial reflector mTop " mBottom " mCore thermal output MW
Design pressure bar" temperature C
Saturated steam temp. C
Superheated steam " C
Shielding radial thickness inStainless steel mm
Heavy water mm
Irradiation flux atvessel wall n/cm sek
(E - 1 MeV)Vessel inner diameter mCylindrical shell
thickness in vessel•steel mm
Vessel steel '
Vessel height mControl rod positionsFuel element handling
penetrationsSuperheater penetrations in
bottom dome
1) Steels according to Table 2,2) Estimated values3) Not penetrating the vessel
Åge staPHWR
3, 613.04
0 . 3
0 . 3
0.3rf» ,
/ 65\(125)
40
251
150
21
1.2* 109
4.555
65
carbon-manganese
9.5
27 + 2
37
page 17.
MarvikenBHWR
4,905.02
0 . 3
0 . 3
0 . 3
570
57.5
272
263
500
50
110
92 )3-4 • 1<K
5.22
61
low- alloy
22. 1303>
1
30
ProjectStudyPHWR-400
4, 66
5.50
0 . 3
0 . 3
0 . 3
1200
80
293
90
130
92)4. 2 • 107
5. 10
90
low-alloy
14. 0
12
Ttop lidY removal
ProjectStudyBashful-500
4.83
4.83
0.330.330.331360
77
291
283
500
(-70)
(-45)
92)-4-6* 107
5.72
98
low-alloy
24.0373)
1
40
- 14
Vessel steels and strength evaluation
In Fig. 12 the specification for the Ågesta vessel steel is given and
in Fig. 13 the impact qualities of the virgin material before fabrication
are demonstrated. From most aspects this steel is quite wellknown
beeing a fine grain treatment modification of a Swedish standardized
pressure vessel steel. The requirement of extraordinary low cobolt
content for nuclear use is representative for the period when the Ågesta
specification was decided. From table 2 and Fig, 14, however, it can
be read that the continued use of a vessel steel with such modest strength
values would cause rattier high wall thickness and as a result of that
quite impossible vessel component weight especially by the larger
vessels. The welding procedures and effective inspection possibilities
are also seriously negatively affected by increasing wall thickness. The
evaluation of thermal stresses resulting from blocked transient thermal
strains is also considered to give strong arguments against thick ma-
terials. It is then an automatic consequence that steels with higher
strength values and still preserved good behaviour in fabrication and
use must be given keen attention. The strength calculation values,
38 - 41 kp/mm at actual design temperatures, given in table 2, are
representative for low-alloy vessel steels obtainable from Swedish
steel-makers today. For the Marviken BHWR reactor vessel the design
and manufacturing pretest work with the Fortiweld Normal steel is
now going on. This is a boron micro-alloyed fine grain treated carbon
steel and gives in normalized condition a yield point value of minimum
45 kp/mm at room temperature and is since some years used in
comparatively large conventional pressure vessels. As for Charpy
impact values this steel is specified for guarantee of 3, 5 kpm/cm
(25 ft. lbs) at 0 C, For ordinary carbon vessel steels the specified
Charpy impact value according to the Swedish Pressure Vessel Code
is 2,6 kpm/cm2 (15 ft.lbs) at -20 °C.
As can be computed from estimated neutron flux data in table 1
the integrated irradiation damage dose (E > 1 MeV) upon the vessel
wall for the Marviken BHWR reactor would be in the order of 3 * 10 n/em
- 15 -
at 30 years total life time and utilisation rate of 80 %. According to
preliminary results from irradiation tests upon this steel this inte-
grated dose might give a fairly large contribution to the rise of brittle
fracture propagation transition temperature. It is today a bit early
to state wether this would cause special requirements as to the
operation conditions for the reactor. If, however, the safeguard
evaluation of the embrittling behaviour would tend to give severe
restrictions in the operational schedule it seems likely that a
medium-strength vessel steel would be chosen this time. Basical
experiments and evaluation work have to be done in order to establish
more explicit use of the scattered and un-correlated knowledge of
irradiated steel behaviour.
The calculation and evaluation of strength conditions for the
ductile behaviour of reactor vessel steels are in some respects
carried out with more care than what is prescribed by pressure vessel
codes applied upon ordinary vessel with dangerous contents. With
respect to undisturbed membrane stresses and mean stress values
the considerations have given the result that no argument exists for
a more conservative attitude. The unofficial provisional requirements
used as additions within this work are specifically valid for thermal
transient stresses and bending stresses. The following list of factors
which can form different patterns for the evaluation of safety factors
gives the situations
Type of loading,
Uncertainly in load evaluation,
Inherent stress conditions,
Real correlation stress verses strain,
Multiaxial stress-strain correlations (plastic yield behaviour criteria),
Deformation hardening and Bauschinger effect,
Relaxation (creep at low temperatures),
Low cycle fatigue,
Corrosion,
Normally existing material defects,
Faultive material,
Influence of fabrication tolerances,
Compatibility between different materials,
Degree of statical indeterminate condition,
Uncertainly in computing methods.
The value of such a xather comprehensive evaluation model de-
pends entirely upon, first real knowledge of reactor operating con-
ditions and second,upon well correlated practical and experimental
experience from vessel behaviour as well in design details as in
material characteristics.
- 17 -
1.
2 .
3 .
4 .
5.
6.
Design pressure
Design temperatureInner diameterVessel steel type
Cylindrical wallthickness -.'(exclusive claddingmaterial)
Bottom dome wallthickness
ALTERNATIVE
5.
5.
t)2)
3)
4)
5)
6)
1 Cylindrical wallthickness for steelaccording to note 1)
2 Cylindrical wallthickness for low-alloy steel accordingto note 4)
Table 2.
bar
°Cm
mm
mm
mm
mm
Reactor
ÅgestaPHWR
40
250
4.555
Vessel Dala
carbon- ,\manganese '
65
65
65
Stress calculation value at actual designU It II
n it it
M If It
Hemispherical shapeAllowable hoop stress
ti i
t) !
t! I
t n
i n
PHWR--400
80
293
5. 10low- .alloy '
90
905>
165
75
temperaturei i
n
M
calculation according to theSwedish Pressure Vessel Code, 1959.
Marviken--BHWR
57.5
272
5.22
low- 3 ,alloy >
61
95
114
52
24 kp/j
38 "41 »
46 "
Bashful--500
77
291
5.72lOW- oy
alloy L)
98
165
180
80
2tim
- 18 -
Fabrication in shop or at site
The size development of heavy water reactor pressure vessels
in Sweden during the next ten years has already been described, Fig. 15,
The rapid increase of the over all dimensions and weights needs a care-
ful investigation of the suitableness of fabricating the vessel in shop, at
site or a combination of the two. A survey of the requirements for a
heavy water reactor pressure vessel as to weld procedure, machiningj
tolerances, final assembly, testing and adjusting gives a distinct ad-
vantage for shop fabrication. Further it is good reason for a statement
that a complete site erection from pressed plates similar to the fabri-
cation of gas cooled reactors in England is more or less impossible.
These facts give rise to the conclusion that a combined fabrication in
shop and at site presupposes that the site must be equipped with a
fabrication shop for putting together largest possible prefabricated
components. Such a shop at site must have facilities for welding,
machining, lifting, stress relieving etc. A good example of this
combined fabrication is the twelve 350 tons heat exchangers for
Trawsfynydd in North Wales.
A complete shop fabrication gives immediately rise to the problem
of transporting the vessel from shop to site. The original intention as
to the Agesta pressure vessel was to transport it a short distance by
rail to the coast and then ship it to site, A combination of delivery date
and the special ice conditions in Sweden did change that scheme to a
complete railway transport. The departure from Degerfors of the
pressure vessel, the top cover and the outer thermal shield is shown
in Fig. 16. This transport item with a diameter of more than 5 meter
and a weight of approximately 200 tons gave one of the most complicated
transportations ever made in Scandinavia and is impossible to repeat
for the much bigger vessel to Marviken, where the original plan for
Ågesta has to be used with the modification that the Marviken vessel
must be floated to site. It is also possible to predict that it is very
likely that such a transportation scheme even can be used for a
600 MW BHWR pressure vessel, which conclusion is based of to-day's
- 19 -
knowledge of design and steel properties. Consequently, for the next
TO years reactor construction in Sweden it seems possible to stick to
shop fabrication without serious extrapolation of to-day's knowledge,
provided that the site is situated on or close to the coast and that the
vessel can safely be taken out of the water and moved to site.
Special shop requirements due to size, weight and design of the vessel
The fact that shop fabrication is a distinct advantage combined
with the above conclusions regarding transport increases the interest
to point out the special shop requirements to make a proper job. The
Marviken pressure vessel with an assembly height of 22. 1 m, a maxi-
mum diameter of almost 6 m and with requirement for a maximum lift
of almost 200 tons gives a very clear answer as to the shop dimensions,
overhead crane capacity and facilities for forming, welding, machining
and stress relieving.
There is no doubt about that there is an increased demand for
heavier pressure vessels from the chemical process industry, oil and
petrochemical industry etc., but the above mentioned example of require-
ments is - generally speaking - ja front of the normal development owing
to the fact that such sizes usually can be prefabricated in shop and put
together at site.
One of the main differences between a heavy water reactor pressure
vessel and an ordinary vessel of the same size is the tolerances. For
the Agesta reactor vessel the shell radius tolerance requirements was
- 2 , 5 mm on a radius of 2, 3 m e. g, 0, 2 %, which is 5 times closer
than the code rules in Sweden and USA prescribe for an ordinary vessel.
It is obvious that these close tolerances require special tools for for-
ming, special studies and equipment for welding and special purpose
machining facilities.
Due to the fact that the design and the method of fabrication do not
permit an adjustment of a mistake require special equipment and trained
- 20 -
engineering capacity in order to carry out full scale protesting. A
good example is the fabrication of the flat top cover for Åge sta, which
is a complicated honeycomb structure of 50 mm steel plate. One stage
of the fabrication is shown in Fig. 17. When the lower closing plate
was finally combined with the grid it was neces.sary to carry, out the
welding with aid of a mirror , which is shown in Fig, 18, A repair
of these welds was impossible. Of that reason a thorough study was
made as to the dimensional changes and weld quality on full scale test
specimens before the fabrication started. Some more examples are
given below.
Shop fabrication and inspection
. A statement that a thourough knowledge of the material properties
and behaviour during shop fabrication is true in all pressure vessel
production. It is no overstatement to say that this knowledge is more
important in a fabrication of a heavy water reactor pressure vessel
than it normally would be. Here it is only possible to give some examples
such as hot deforming properties and spring back by bending and pressing;
dimensional changes by cooling from hot forming, welding and stress
relieving; changes of mechanical properties in weld metal, plates and
forgings by heat treatment. Thesa examples point out the necessity for
a close contact between a well equipped and highly trained laboratory
and the shop fabrication in order to be sure that the final product is
in full accordance with the specification as to design and mechanical
properties.
It can be worth mentioning that in order to be able to judge
possible changes in dimensions and material properties during the
fabrication of the Agesta pressure vessel a series of full scale tests
were made. These included for example:
1) Hot pressing and heat treatment of 85 mm clad steel plate for the
outer shell of the top cover,
2) Cold pressing and stress relieving of 70 mm plate for the shell,
3) Hot pressing, heat treatment etc. for a 100 mm steel plate for the
bottom closure.
- 21 -
The above mentioned tests verified, the methods to keep the ma-
terials properties according to the specification. On the contrary the
welding tests showed that some alterations from normal procedure
had to be made and that new welding methods sometimes had to be
developed.
Some fabricating problems during a shop fabrication of a heavy-
water reactor pressure vessel will be illustrated in the following
by giving a short description of some production stages of the Ågesta
vessel.
The tank bottom started with welding of pressed sections, which
is shown in Fig. 19. This spherical shaped segment was hot flanged
in a gap press, see Fig, 20, This flanging operation had at the same
time to meet the above mentioned close diameter tolerance for the
vessel and the accurate knuckle radii for the ellipsoidical shape of the
bottom.
The main welding me thods used were manual arc welding and
submerged arc welding. Preheating had to be used all the time except
for the stainless steel welding. The tank bottom being welded on to
the shell from the inside of the vessel by using submerged arc welding
is shown in Fig, 21, where the eight main nozzles for inlet and outlet
of the coolant and the central support and locking for the outer thermal
shield is visible,
A very complicate internal reactor component from the welding
and machining point of view was the water distribution box, which is
shown in Fig. 22,
The necessity for having facilities for stress relieving is illustra-
ted in Fig* 23, where the pressure vessel just is taken out of the furnace.
The top cover is penetrated by a large number of tubes for fuelling
operation and application of control rod drives. All these tubes had to
be welded in and during these operations the top cover was constantly
preheated for about six weeks, A view of the top cover after the tube
welding is shown in Fig, 24, The charging tubes and all small tubes for
control and detecting applications were welded at site. The top cover
after completing of this job is shown in Fig, 25, where the cover is just
going to be placed on the tank portion of the vessel.
The inspection program was very extensive and covered at first
the steel production, plate rollings casting, forging, tubing etc. before
the vessel fabrication started. In this fabrication the inspection covered
weld operator tests, weld procedure tests, X-ray and ultrasonic in-
vestigations and testing of steel coupons for control of the mechanical
properties all the way through the fabrication.
It may be of some interest to mention a special investigation,
which was made on welds representing the submerged arc type in the
tank bottoms Fig» 27, and in the shell of the vessel, Fig, 26,
Fig. 27 shows some results from tensile and shear tests on ma-
terial from a weld, representing the submerged arc welds in the bottom
head. After welding the material has been normalized and stress re-
lieved for a considerable time.
Both tensile and shear tests show that there is no significant
difference between surface and centre of the plate material but that
there are differences in the weld metal. The centre part of the weld
has a somewhat higher analysis according to a greater proportion of
base metal being melted and mixed with the weld metal. Thie gives
the centre part of the weld about the same tensile and shear test
values as the base metal. In the other parts of the weld these values
are lower according to a weaker chemical analysis, but the tensile
test results still meet the UTS-specification of the plate material»
- 23 -
Fig. 26 shows some results from a similar weld that has been
stress relieved only. Here the normal harder peaks in the heat affec-
ted zones can be observed and the weld metal shows higher values
than in the previous case.
Interesting test material was received when eight discs were cut
out in the tank bottom for the penetrations for the main nozzles for the
coolant. This material had under identical circumstances passed the
same operations as the tank bottom followed by the stress relieving
treatment of the vessel» A very thorough investigation was carried out
as to microstructure and mechanical properties of the base metal and
the welded joints. The results confirmed those obtained by the pretests
and can be summarized in the following way,
a) The yield strength of the pressure vessel steel decreases slightly
after hot pressing,renormalizing and prolonged stress relieving
but lies still within the specification.
b) The impact-transition curve for the pressure vessel steel shifts
to a slightly higher temperature by especially prolonged stress
relieving.
c) Tensile specimens taken crosswise to the manual arc welded joint
showed a slight drop in the yield strength compared with the pretests
but the values obtained were still within the specifications. Impact
testing of the weld metal showed that this had kept its good impact
properties.
d) Tensile specimens taken crosswise to the submerged arc welded
joint did not show any difference in yield strength compared with
the pretests". The impact strength of this weld metal was, as the
pretests had shown, inferior to that of the base metal and the
manual arc weld metal, but still within the specification require-
ments.
Surplus material of the above mentioned type and origin is de-
livered to the customer - AB Atomenergi - -who has prepared tensile
and impact tests specimens, which will be put into the eleven tests
- 24 -
specimen channels in the outer thermal shield of the reactor. This ma-
terial will give interesting information of the radiation damage effect
of the pressure vessel steel at different intervals during the life, time
of the reactor.
Summary
The general desire by the power reactor process makers to in-
crease power rating and their efforts to involve more advanced thermal
behaviour and fuel handling facilities within the reactor vessels are
accompanied by an increase in both pressure vessel dimensions and
various difficulties in giving practical solutions of design, mate rials
and fabrication problems. In any section of this report it is emphasized
that difficulties and problems already met with will meet again in the
future vessels but then in modified forms and in many cases more per-
tinent than before. As for the increase in geometrical size it can be
postulated that with use of better materials and adjusted fabrication
methods the size problems can be taken proper care of. It seems
likely that vessels of sufficient large diameter and height for the
largest power output, which is judged as interesting in the next ten
year period, can be built without developing totally new site fabri-
cation technique. It is, however, supposed that such a fabrication
technique will be feasible though at higher specific costs for the same
quality requirements as obtained in shop fabrication.
By the postulated use of more efficient vessel material with
principally the same good features of easy fabrication in different
stages such as preparation, welding, heat treatment, etc. as ordi-
nary or slightly modified carbon steels,the increase in wall thickness
might be kept low. There exists, however, a development work to be
done for low-alloy steels to prove their justified use in large reactor
pressure vessels. The problem of brittle fracture has haunted many
technicians in various fields since it was first observed upon subjects
of rather rough and undefined design and fabrication standard. The fact
- 25 -
that irradiation gives embrittling effects in vessel steels is in itself
out of doubt. The question of what this rise of ductility transition
temperature would really mean to vessels fabricated at the best
practice of manufacturing is still not answered today. The need for
more accurate definition of what safety evaluation against brittle
fracture should cover is obvious.
Another interesting problem complex is connected to the demand
for higher process temperatures and more sophisticated design in
local parts of the vessel. This will quite rapidly bring the aspects
of creep and thermal fatigue within the complex of questions to be
dealt with.
Aside from these advanced aspects the interest in building reac-
tor vessels at lower cost rates will give a full batch of problems even
if the prestanda of the vessel would not be required to increase physi-
cally» Although there may have been no total failures of reactor vessels
in service until now the serious situation is demonstrated by the fact
that during fabrication, inspection and assembly work threatening de-
fects have been revealed. In some cases the observation was made
as late as when the vessel was already assembled to circuitry piping
in the plant. The resulting time élelay and additional money expenses
have of course a tendency to give rise to unfavourable remarks upon
the present aims of nuclear vessel technology. The true situation of
nuclear vessel work of today might be stated so that all the way through
each problem treatment involves the very best of an ever increasing
quality standard practice completed with real extrapolations of the
probability judgment of yet sparely clarified effects of various physical
influences. As often will be the result from handling technical problems
this way the costs have a vivid tendency to go high. Many of the extra
considerations in design and choice of structure materials, fabrication
methods, quality control and pertinent inspection are no doubt justified
by the absolute need for safety against nuclear hazards during an eco-
nomical vessel life time. It could, however, be suspected that the line
- 26 -
of conservative technical decisions in any problem is a bit unbalanced
and not really giving that superior safety, which is justified to pay for.
Thus selective studies of which factors in pressure vessel work do
really inflict upon vessel safety are needed, so that technical decisions
code regulated or not - leading to specifically high costs without adding
any real or very small favour points in safety and long life vessel use
could be eliminated or adequately ranged.
RN/EL
COOLING SYSTEM FOR CONTROL RODS
BORON INJECTION PIPE
_ \ _ -\ PIPE FOR EMTING REACTOR LID
GUID FUNNEL FOR,
FUEL ELEMENT
REACTOR PRESSURE VESSEL2 FILLER RING
3 FILLER BODY
4 OUTER THERMAL SHIELD
INNER THERMAL SHIELD
6 WATER HEADER
7 LEAD OFF RING
8 LID THERMAL SHIELD9 VESSEL LID
10 FLANGE ASSEMBLY
11 LOCKING RtNG
12 CENTRAL BOLT
13 NUT
15 SEALING RING
16 LOCKING PIN
17 GUIDING F IN
18 GUIDING BLOCK FOR VESSEL
19 GUIDING BLOCK FOR BOTTOM RADIATION SHIELD
20 SUPPORT RING
21 SUPPORT BRACKET
SECTION OF ÅÖESTA REACTOR VESSELAB ATOMENERGI
Pressure Vesselwith filler body
III
Fixed Blockfor insulation
Guiding blockfor Vessel'souter ThermalShield
Filler Body(Outer Piece)
(Central Piece)
Outlet Nozzle
Interspece water Intake nozzleInlet
Modified Torv
Bracket forTorus
SuspensionBracket forbottom flangering
Guidance forVessel inBiologicalShield
ÅGESTA REACTOR VESSELTANK DESIGN
Reactor Lid with
Upper Thermal Shield
o oen
V >-3
3 >S w
°0
H
4 Pipes to pressurize*1 system
Loading stand
pipe with
control rod
Thermocouple
Detection Tube
Fuel
Canning Leak
detection
Outlet header for
Lid cooling system
\
Sealing Tube
Torus
Guide for Lid
thermal shield
Holding Bolt for
upper thermal shield
in Lid
Loading Intake header for
Standpipe Lid cooling system
Inspection Tube
Fuel Canning Leak
Detection Tube
Reactor Vessel Wall
Outer thermal
shield
i i
pSERVICE WITHBOILING WITHSUPERHEATING
SERVICE WITHBOILING WITHOUTSUPERHEATING
vVI.
REACTOR PRESSURE VESSEL
RADIAL THERMAL SHIELD
BOILER CHANNELS 151 OFF
SUPERHEATER CHANNELS 30 OFF
CONTROL RODS 30 OFF
t NEUTRON DETECTORS 9 OFF
/T*\ TRANSPORT CHANNEL FOR\\J CONTROL RODS AND FUEL
ELEMENTS 1 OFF
MARVIKEN BHWR LATTICE
AB ATOMENERGI
VII
\ / / /
SUPERHEATED STEAM
5/5 2218
BEFORE THROTTLING
22Cr/f2ri,'WELDED CLADDING
\ \ \ \ \
\ \ \
COMPOUNDED IN 2 MM LAYERSOR k MM WELDED CLADDING
\ \
\ X \ \ \ \ \ \ \
\ \ \ \ \ \ \ \
SIS2324 Ti'rArtAlt /ricoHtL
5/S 2333
ef S/3S333
MARVIKEN BHIVR SUPERHEATER NOZZLES IN
BOTTOM DOME. PROPOSED TEST MODEL DESIGN
VIII.
3/90
3!
-_•=. = -x - .
FLANGE DESIGN OF ÅGESTA TYPE MODIFIED
FOR MARVIKEN BH.VR
IX
Sfoo
J
Preliminary dimensions
PHWR-400 VESSEL WITH MODERATOR
TANK AND SHROUD HEAD
X .
FIG 10
SGALE 1 : 3 MODELOF ÅGESTA VESSEL
FIG 11 TEST MODEL OF FLATTOP COVERÄGESTA VESSEL
XI
FIG 12
CARBON -MANGANESESTEEL, FOR ÅGESTA .VESSEL SPECIFICA-TION
UODEHOLMS A B
Degerlors Järnverk
Carbon-Manganese - Steel2103-R3
ÄgestaNuclearReactor
Composition
C
Si
Mn
p
SCr
Ni
Cl!
Co
N
»At11
max. 0,16 "
0,15-0,5
max. 1,6 »
II 0,02
II 0,03II 0,1
II 0,1
" 0,1.
« 0,020
II 0,015
7.II
II
„n
n
II
|| (200I I
C max. 0,15-Mn max.
" ° ' M ' n
ppm)
1,7
1.8
Mechanical Properties
Yield Strength mm 30 kp/mm(Lower yield point)
(a 30mm)Ultimate TensileStrength 48-58 kp/mm
Elongationon 200mm mm. 18 *U
Impact Strength .(Charpy-V.LS) min. 2,6 kpm/cm
(15 f t lbs)at-20'C
Heat Treatment Nnrmnhcmrj
The Steel is used as:
@Q£li'rLg_DiQt̂ riöL_Q.i EonsLngs^m
Shell of the vesselGrid in the lidUpper plate in the lid Bottom headSupporting ring in 5hell of the lidlocking devise
Flange of the shellFlange of the lidLoose flanges
Lower plate in the lid Nozzles in thebottom head
Imcact properties of 2103-R3 steel.
Normalised materialirnm/rrn Charpy-V specimens\^JI l l rv l l l
2423
2221
20
191817161514
13
1211
109B7
65
432
1
70mm clad steel plateForging 500»320mm
////
/ /
/
//II
/
/: // /
/ // '• /
/ '• // / /
Longitudinal
Transvers
/ ^/
/
//
/f
Temperature C
FIG 13
IMPACT QUALITIES OF THEÅGESTA VESSEL STEELUNIRRADIATED. (FORIRRADIATION DOSE INTE-GRATED- 2xlO18
TRANSITION TEMPERATUREIS RISED LESS THAN 50° C).
-U0 -120 -100 -80 -60 -40 -20 0 +20 +40
XII.
200 mm . .
150 mm ..
100 mm . .
50 mm
Cylindrical shellthickness
Carbon-mangalese steeltable 2 note l)o =30 kp/mmy. p. Vl
Low-alloy steel
table 2 note 2) and 3)
o =45-50 kp/mmy. p. w
Low-alloy steel table 2 note
o =55 kp/mmy. p. F /
4)
(Design pressure) x (inner diameter)
200 300 400 (bar x m)
tÄGESTA
PHWRMAR VIKEN
BHWRPHWR--400
BASHFUL-500
FIG 14 INFLUENCE OF STEEL QUALITY UPONWALL THICKNESS
5
25 m •
20 a -
15 m -•
10 m
5 m
0 m
J )?f/7'
ÅGESTA PHWR PHKR-400 MARVIKEN BHWR
Scale 1:200FIG 15 SCHEMATIC STUD? IN SIZE Ö
HM
XIV.
FIG 16DEPARTURE FROM SHOP OFMAIN PARTS OF THEÅGESTA VESSEL
FIG 17
ÅGESTA VESSEL.TOP COVER HONEY COMB GRID INWELDING POSITIONER
FIG 18
SPECIAL WELDING METHODUSED IN NARROW BACK-SPACEIN TOP COVER.ÅGESTA VESSEL
: Diagram over Ihe principle used for welding in the lid bythe aid of a mirror
xv.
PIG 19
SEAM WELDING OP BOTTOM DOMEPRESSED SECTIONS.ÅGESTA VESSEL
PIG 20
CYLINDER FLANGE HOTFORMING OP DOME.ÅGESTA VESSEL
FIG 21
SUBMERGED ARC WELDING OF BOTTOMDOME TO THE CYLINDER SHELL
XVI
-«• * • • ' « . »*» ^ j ijji» «
w < \
••<j
FIG 22 TEST ASSEMBLY OF FUEL, ELEMENTFUNNELS INTO WATER DISTRIBUTIONHEADER. ÄGESTA VESSEL
FIG 23
STRESS RELIEVINGFURNACE BEHIND THEÄGESTA VESSEL
XVII
vA.
• \
FIG 24 ÅGESTA SITETOP LID BEFOREWELDING ON THESTAND PIPES
FIG 25
ÅGESTA SITESTAND PIPES AND SMALLSIZE PIPING ASSEMBLED.LID PREPARED FORCLOSING REACTORVESSEL.
XVIII.
Results trom shear tests on mikrospecimensfrom a submerged arc weld in plate of 2103-R3 quality.
PIG 26
MICROTESTING OP WELD ANDTRANSITION ZONE MATERIAL.STRESS RELIEVING ONLY
Shear strength
kp/mm
Heat treatment after welding Stress relieving
FIG 27
MICROTESTING OF WELD ANDTRANSITION ZONE MATERIAL.NORMALIZING AND STRESSRELIEVING
Results from tensile and shear lesls on mikro-SD&cimens from q submerged arc weld in a100mm plate of 21Q3-R3 quality
UTS
Heat treatment after welding Normalizing and stressrelieving
LIST OF PUBLISHED AE-REPORTS
1—29. (See the back cover of earlier reports.)30. Metallographic study of the isothermal transformation of beta phase in
zircaloy-2. By G. Östberg. 1960. 47 p. Sw. cr. 6:—.
31. Calculation of the reactivity equivalence of control rods in the secondcharge of HBWR. By P. We'ssglas. 1961. 21 p. Sw. cr. 6:—.
32. Structure investigations of some beryllium materials. By I. Fäldt and G.Lagerberg. 1960. 15 p. Sw. cr. 6:—.
33. An emergency dosimeter for neutrons. By J. Braun and R. Nilsson. 1960.32 p. Sw. cr. 6:—.
34. Theoretical calculation of the effect on lattice parameters of emptyingthe coolant channels in a D2O-moderated and cooled natural uraniumreactor. By P. Weisglas. 1960. 20 p. Sw. cr. 6:—.
35. The multigroup neutron diffusion equations/1 space, dimension. By S.Linde. 1960. 41 p. Sw. cr. 6:—.
36. Geochemical prospecting of a uraniferous bog deposit at Masugnsbyn,Northern Sweden. By G. Armands. 1961. 48 p. Sw. cr. 6:—.
37. Spectrophotometric determination of thorium in low grade minerals andores. By A.-L. Arnfelt and I. Edmundsson. 1960. 14 p. Sw. cr. 6:—.
38. Kinetics of pressurized water reactors with hot or cold moderators. ByO. Norinder. 1960. 24 p. Sw. cr. 6:—.
39. The dependence of the resonance on the Doppler effect. By J. Rosén.1960. 19 p. Sw. cr. «:—.
40. Measurements of the fast fission factor (.<•) in UOj-elemenls. By O. Ny-lund. 1961. Sw. cr. 6:—.
44. Hand monitor for simultaneous measurement of alpha and beta conta-mination. By I. O. Andersson, J. Braun and B. Söderlund. 2nd rev. ed.1961. Sw. cr. 6:—.
45. Measurement of radioactivity in the human body. By I. O . Anderssonand I. Nilsson. 1961. 16 p. Sw. cr. 6:—.
46. The magnetisation of MnB and its variation with temperature. By N.Lundquist and H. P. Myers. 1960. 19 p. Sw. er. 6:—.
47. An experimental study of the scattering of slow neutrons from HjO andD2O. By K. E. Larsson, S. Holmryd and K. Otnes. 1960. 29 p. Sw. cr. 6:—.
48. The resonance integral of thorium metal rods. By E. Hellstrand and J.Weitman. 1961. 32 p. Sw. cr. 6:—.
49. Pressure tube and pressure vessels reactors; certain comparisons. By P.H. Margen, P. E. Ahlström and B. Pershagen. 1961. 42 p. Sw. cr. 6:—.
50. Phase transformations in a uranium-zirconium alloy containing 2 weightper cent zirconium. By G. Lagerberg. 1961. 39 p. Sw. cr. 6:—.
51. Activation analysis of aluminium. By D. Brune. 1961. 8 p. Sw. cr. 6:—.52. Thermo-technical data for D2O. By E. Axblom. 1961. 14 p. Sw .cr. 6:—.53. Neutron damage in steels containing small amounts of boron. By H. P.
Myers. 1961. 23 p. Sw. cr. 6:—.54. A chemical eight group separation method for routine use in gamma
spectrometric analysis. I. Ion exchange experiments. By K. Samsahl.1961. 13 p. Sw. cr. 6:—.
55. The Swedish zero power reactor R0. By Olof Landergård, Kaj Cavallinand Georg Jonsson. 1961. 31 p. Sw. cr. 6:—.
56. A chemical eight group separation method for routine use in gammaspectrometric analysis. I I . Detailed analytical schema. By K. Samsahl.18 p. 1961. Sw. cr. 6:—.
57. Heterogeneous two-group diffusion theory for a finite cylindrical reactor.By Alf Jonsson and Göran Näslund. 1961. 20 p. Sw. cr. 6:—.
58. Q-values for (n, p) and (n, a) reactions. By J. Konijn. 1961. 29 p. Sw. cr.6:—.
59. Studies of the effective total and resonance absorption cross section forzircaloy 2 and zirconium. By E. Hellstrand, G. Lindahl and G. Lundgren.1961.26 p. Sw. cr. 6:—.
60. Determination of elements in normal and leukemic human whole bloodby neutron activation analysis. By D. Brune, B. Frykberg, K. Samsahl andP. O. Wester. 1961. 16 p. Sw. cr. 6:—.
61. Comparative and absolute measurements of 11 inorganic constituents of38 human tooth samples with gamma-ray spectrometry. By K. Samsahland R. Söremark. 19 p. 1961. Sw. cr. 6:—.
62. A Monte Carlo sampling technique for multi-phonon processes. By ThureHögberg. 10 p. 1961. Sw. cr. 6 ™ .
63. Numerical integration of the transport equation for infinite homogeneousmedia. By Rune Håkansson. 1962. 15 p. Sw. cr. 6:—.
64. Modified Sucksmith balances for ferromagnetic and paramagnetic mea-surements. By N. Lundquist and H. P. Myers. 1962. 9 p. Sw. cr. 6:—.
65. Irradiation effects in strain aged pressure vessel steel. By M. Grounesand H. P. Myers. 1962. 8 p. Sw. cr. 6:—.
66. Critical and exponential experiments on 19-rod clusters (R3-fuel) in heavywater. By R. Persson, C-E. Wikdahl and Z. Zadwörski. 1962. 34 p. Sw. cr.6:~~.
67. On the calibration and accuracy of the Guinier camera for the deter-mination of interplanar spacings. By M. Möller. 1962. 21 p. Sw. cr. 6:—.
68. Quantitative determination of pole figures with a texture goniometer bythe reflection method. By M. Möller. 1962. 16 p. Sw. cr. 6:—.
69. An experimental study of pressure gradients for flow of boiling water ina vertical round duct, Part I. By K. M. Becker, G. Hernborg ana M. Bode.1962. 46 p. Sw. cr. 6:—.
70. An experimental study of pressure gradients for flow of boiling water ina vertical round duct. Part I I . By K.M. Becker, G. Hernborg andM. Bode.1962. 32 p. Sw. cr. 6:—.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
83.
84.
85.
86.
87.
88.
89.
90.
91.
92.
93.
94.
95.
96.
97.
98.
99.
100
101
102
103.
104.
The space-, lime- and energy-distribution of neutrons from a pulsedplane source. By A. Claesson. 1962. 16 p. Sw. cr. 6:—.One-group perturbation theory applied to substitution measurements withvoid. By R. Persson. 1962. 21 p. Sw. cr. 6:—.Conversion factors. By A. Amberntson and S-E. Larsson. 1962. 15 p. Sw.cr. 10:—.Burnout conditions for flow of boiling water in vertical rod clusters.By Kurt M. Becker. 1962. 44 p. Sw. cr. 6-.—.Two-group current-equivalent parameters for control rod cells. Autocodeprogramme CRCC. By O. Norinder and K. Nyman. 1962. 18 p. Sw. cr.
On the electronic structure of MnB. By N. Lundquist. 1962. 16 p. Sw. cr6:—.The resonance absorption of uranium metal and oxide. By E. Hellstrandand G. Lundgren. 1962. 17 p. Sw. cr. 6:—.Half-life measurements of 'He, " N , »O, *>F, »Al, "Se™ and ™Ag. By J.Konijn and S. Malmskog. 1962. 34 p. Sw. cr. 6:—.Progress report for period ending December 1961. Department for ReactorPhysics. 1962. 53 p. Sw. cr. 6:—.Investigation of the 800 keV peak in the gamma spectrum of SwedishLaplanders. By I. O. Andersson, I. Nilsson and K. Eckerslig. 1962. 8 p.Sw. cr. 6:—.The resonance integral of niobium. By E. Hellstrand and G. Lundgren.1962. 14 p. Sw. cr. 6:—.Some chemical group separations of radioactive trace elements. By K.Samsahl. 1962. 18 p. Sw. cr. 6:—.Void measurement by the (y, n) reactions. By S. Z. Rouhani. 1962. 17 P.Sw. cr. 6:—.Investigation of the pulse height distribution of boron trifluoride pro-portional counters. By I. O. Andersson and S. Malmskog. 1962. 16 p.Sw. cr. 6:—.An experimental study of pressure gradients for flow of boiling waterin vertical round ducts. (Part 3). By K. M. Becker, G. Hernborg and M .Bode. 1962. 29 p. Sw. cr. 6:—.An experimental study of pressure gradients for flow of boiling waterin vertical round ducts. (Part 4). By K. M. Becker, G. Hernborg and M.Bode. 1962. 19 p. Sw. cr. 6:—.
Measurements of burnout conditions for flow of boiling wafer in verticalround ducts. By K. M. Becker. 1962. 38 p. Sw. cr. 6:—.
Cross sections for neutron inelastic scattering and (n, 2n) processes. ByM. Leimdörfer, E. Bock and L. Arkeryd. 1962. 225 p. Sw. cr. 10:—.On the solution of the neutron transport equation. By S. Depfcen. 1962.43 p. Sw. cr. 6:—.Swedish studies on irradiation effects in structural materials. By M.Grounes and H. P. Myers. 1962. 11 p. Sw. cr. 6:—.The energy variation of the sensitivity of a polyethylene moderated BFjproportional counter. By R. Fräki, M. Leimdörfer and S. Malmskog. 1962.12 p. Sw. cr. 6:—.
The backscatteriniM. Leimdörfer. 19<
I of gamma radiation from plane concrete walls. By2. 20 p. Sw. cr. 6:—.
The backscattering of gamma radiation from spherical concrete walls. ByM. Leimdörfer. 1962. 16 p. Sw. cr. 6:—.
Multiple scattering of gamma radiation in a spherical concrete wallroom. By M. Leimdörfer. 1962. 18 p. Sw. cr. 6:—.
The paramagnetism of Mn dissolved in « and ft brasses. By H. P. Myersand R. Weslin. 1962. 13 p. Sw. cr. 6:—. r
Isomorfic substitutions of calcium by strontium in calcium hydroxy-apatite. By H. Christensen. 1962. 9 p. Sw. cr. 6:—.A fast time-to-pulse height converter. By O. Aspelund. 1962. 21 p. Sw. cr.6:—.Neutron streaming in D2O pipes. By J. Braun and K. Randen. 1962.41 p. Sw. cr. 6:—.The effective resonance integral of thorium oxide rods. By J. Weitman.1962. 41 p. Sw. cr. 6:—.
1. Measurements of burnout conditions for flow of boiling water in verticalannuli. By K. M. Becker and G. Hernborg. 1962. 41 p. Sw. cr. 6:—.
. Solid angle computations for a circular radiator and a circular detector.By J. Konijn and B. Tollander. 1963. 6 p. Sw. cr. 8:—.
:. A selective neutron detector in the keV region utilizing the "F(n, y)!0Freaction. By J. Konijn. 1963. 21 p. Sw. cr. 8:—.
Anion-exchange studies of radioactive trace elements in sulphuric acidsolutions. By K. Samsahl. 1963. Sw. cr. 8:—.Problems in pressure vessel. Design and manufacture. By O. Hellströmand Ragnar Nilson. 1963. Sw. cr. 8:—.
Förteckning över publicerade AES-rapporter
1. Analys medelst gamma-spektrometri. Av Dag Brune. 1961. 10 s. Kr 6:—.
2. Besträlningsförändringar och neutronatmosfär i reaktortrycklankar —några synpunkter. Av M. Grounes. 1962. 33 s. Kr 6:—.
Additional copies available at the library of AB Atomenergi, Studsvik, Nykö-ping, Sweden. Transport microcards of the reports are obtainable throughthe International Documentation Center, Tumba, Sweden.
EOS-tryckerierna, Stockholm 1963